generally i try to aviod these things but i gotta interject some food for
thought on this line of questioning.
no one but your machinist or engine builder can really reccomend what to
use for a break in lubricant. why-O-why do i say something so silly as
this you may ask? the number 1 reason is it has a lot to do with the
machined tolerances used in the boring or crank turning as some choose a
"loose" assembly and some choose a rather tight tolerance on bearings and
bores.
if your motor was seriously gone through and remachined to specific
tolerances certain oils may not properly lubricate it and during break in
lead to premature failure.
some choose a very light oil just long enough to warm it up and dump the
oil and filter nearly right away while others say 500 to 1000 miles before
a change. it's a very very personal thing with respect to the specific
engine and it's builder. on a loose motor you can run it "like you stole
it" almost right from the first hour of running time , while tight motors
require certain periods of varying use slowly building up to extended
periods of use in order for evrything to "wear in" properly. mineral oils
and semi synthetic or synthetics are yet another can of worms that is best
left to the engine builder to explain why's and how-for's with respect to
each individual rebuild.
i like a loose fast spinning motor personally. i'm a fan of castrol
20-50wt in my tow vehicle and i run straight racing 70wt in my street
bugeye. (yes i warm it up first!) (and straight racing 60wt in my stroker
harley motor).
but! those are motors i built and i know exactly what's in 'em.
chuck.
> I talked to a guy at Elgin Cams today - he said they recommend straight 30
> weight oil to break in a new engine.
>
> I'm breaking in a new 1275 on my street Bugeye right now, and I'm going
to be
> breaking in a new race 948 soon.
>
> I've been using Castrol 20w50. Shoud I be using a different oil for
break-in?
>
> Thanks
>
> Bud Pazur
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